Lachesilla pedicularia is a species of Psocoptera from the family Lachesillidae.[1] It is commonly known as cosmopolitan grain barklouse or cosmopolitan grain psocid and, as these names suggests, it has an almost cosmopolitan distribution.[2]
Lachesilla pedicularia is 1.5-2 mm long. It is often macropterous (with long wings), but brachypterous (with short wings) individuals also occur.[3]
Some features distinguishing this from other species of Lachesilla are the abdomen having brown stripes, the forewing being hairless, wing vein R1 meeting the wing edge almost at a right angle, and several other wing veins being marked with brown.
There are also features in the genitalia. The subgenital plate of females forms a simple curved shape, while the hypandrium of males has simple (not forked) appendages.
This species occurs on the trunks and (to a lesser extent) branches of a range of trees, including beech, birch, broom, oak, pine, spruce, and yew. It is also known from haystacks, straw bales, nests of robins, barns, houses, and stored grain.